/**
* @file
* Ethernet Interface Skeleton
*
*/

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */

/*
* This file is a skeleton for developing Ethernet network interface
* drivers for lwIP. Add code to the low_level functions and do a
* search-and-replace for the word "ethernetif" to replace it with
* something that better describes your network interface.
*/

#include "lwip/opt.h"
#include "lwip/mem.h"
#include "netif/etharp.h"
#include "ethernetif.h"
#include "stm32f4x7_eth.h"
#include <string.h>

/* Network interface name */
#define IFNAME0 's'
#define IFNAME1 't'


/* Ethernet Rx & Tx DMA Descriptors */
extern ETH_DMADESCTypeDef  DMARxDscrTab[ETH_RXBUFNB], DMATxDscrTab[ETH_TXBUFNB];

/* Ethernet Driver Receive buffers  */
extern uint8_t Rx_Buff[ETH_RXBUFNB][ETH_RX_BUF_SIZE]; 

/* Ethernet Driver Transmit buffers */
extern uint8_t Tx_Buff[ETH_TXBUFNB][ETH_TX_BUF_SIZE]; 

/* Global pointers to track current transmit and receive descriptors */
extern ETH_DMADESCTypeDef  *DMATxDescToSet;
extern ETH_DMADESCTypeDef  *DMARxDescToGet;

/* Global pointer for last received frame infos */
extern ETH_DMA_Rx_Frame_infos *DMA_RX_FRAME_infos;

#if NO_SYS
#else
#include "arch/sys_arch.h"
static sys_sem_t eth_input_sem = NULL;
#endif

static void eth_input_thread(void *arg);

/**
 * In this function, the hardware should be initialized.
 * Called from ethernetif_init().
 *
 * @param netif the already initialized lwip network interface structure
 *        for this ethernetif
 */
static void low_level_init(struct netif *netif)
{
    int i;

  /* set MAC hardware address length */
    netif->hwaddr_len = ETHARP_HWADDR_LEN;

    /* set MAC hardware address */
    netif->hwaddr[0] =  2;
    netif->hwaddr[1] =  1;
    netif->hwaddr[2] =  3;
    netif->hwaddr[3] =  5;
    netif->hwaddr[4] =  6;
    netif->hwaddr[5] =  7;

    /* initialize MAC address in ethernet MAC */
    ETH_MACAddressConfig(ETH_MAC_Address0, netif->hwaddr);

    /* maximum transfer unit */
    netif->mtu = 1500;

    /* device capabilities */
    /* don't set NETIF_FLAG_ETHARP if this device is not an ethernet one */
    netif->flags = NETIF_FLAG_BROADCAST | NETIF_FLAG_ETHARP | NETIF_FLAG_LINK_UP;


    /* Initialize Tx Descriptors list: Chain Mode */
    ETH_DMATxDescChainInit(DMATxDscrTab, &Tx_Buff[0][0], ETH_TXBUFNB);
    /* Initialize Rx Descriptors list: Chain Mode  */
    ETH_DMARxDescChainInit(DMARxDscrTab, &Rx_Buff[0][0], ETH_RXBUFNB);

  /* Enable Ethernet Rx interrrupt */
    for(i=0; i<ETH_RXBUFNB; i++)
    {
        ETH_DMARxDescReceiveITConfig(&DMARxDscrTab[i], ENABLE);
    }

#ifdef CHECKSUM_BY_HARDWARE
    /* Enable the TCP, UDP and ICMP checksum insertion for the Tx frames */
    for(i=0; i<ETH_TXBUFNB; i++)
    {
        ETH_DMATxDescChecksumInsertionConfig(&DMATxDscrTab[i], ETH_DMATxDesc_ChecksumTCPUDPICMPFull);
    }
#endif

    /* Note: TCP, UDP, ICMP checksum checking for received frame are enabled in DMA config */
#if NO_SYS
#else
    sys_sem_new(&eth_input_sem, 0);
    sys_thread_new("eth_input_thread", eth_input_thread, NULL, 1024*2, (configMAX_PRIORITIES - 1));
#endif

    /* Enable MAC and DMA transmission and reception */
    ETH_Start();
}

/**
 * This function should do the actual transmission of the packet. The packet is
 * contained in the pbuf that is passed to the function. This pbuf
 * might be chained.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @param p the MAC packet to send (e.g. IP packet including MAC addresses and type)
 * @return ERR_OK if the packet could be sent
 *         an err_t value if the packet couldn't be sent
 *
 * @note Returning ERR_MEM here if a DMA queue of your MAC is full can lead to
 *       strange results. You might consider waiting for space in the DMA queue
 *       to become availale since the stack doesn't retry to send a packet
 *       dropped because of memory failure (except for the TCP timers).
 */

static err_t low_level_output(struct netif *netif, struct pbuf *p)
{
    err_t errval;
    struct pbuf *q;
    u8 *buffer =  (u8 *)(DMATxDescToSet->Buffer1Addr);
    __IO ETH_DMADESCTypeDef *DmaTxDesc;
    uint16_t framelength = 0;
    uint32_t bufferoffset = 0;
    uint32_t byteslefttocopy = 0;
    uint32_t payloadoffset = 0;

    DmaTxDesc = DMATxDescToSet;
    bufferoffset = 0;

    /* copy frame from pbufs to driver buffers */
    for(q = p; q != NULL; q = q->next)
    {
        /* Is this buffer available? If not, goto error */
        if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32)RESET)
        {
            errval = ERR_BUF;
            goto error;
        }

        /* Get bytes in current lwIP buffer */
        byteslefttocopy = q->len;
        payloadoffset = 0;

        /* Check if the length of data to copy is bigger than Tx buffer size*/
        while( (byteslefttocopy + bufferoffset) > ETH_TX_BUF_SIZE )
        {
            /* Copy data to Tx buffer*/
            memcpy( (u8_t*)((u8_t*)buffer + bufferoffset), (u8_t*)((u8_t*)q->payload + payloadoffset), (ETH_TX_BUF_SIZE - bufferoffset) );

            /* Point to next descriptor */
            DmaTxDesc = (ETH_DMADESCTypeDef *)(DmaTxDesc->Buffer2NextDescAddr);

            /* Check if the buffer is available */
            if((DmaTxDesc->Status & ETH_DMATxDesc_OWN) != (u32)RESET)
            {
            errval = ERR_USE;
            goto error;
            }

            buffer = (u8 *)(DmaTxDesc->Buffer1Addr);

            byteslefttocopy = byteslefttocopy - (ETH_TX_BUF_SIZE - bufferoffset);
            payloadoffset = payloadoffset + (ETH_TX_BUF_SIZE - bufferoffset);
            framelength = framelength + (ETH_TX_BUF_SIZE - bufferoffset);
            bufferoffset = 0;
        }

        /* Copy the remaining bytes */
        memcpy( (u8_t*)((u8_t*)buffer + bufferoffset), (u8_t*)((u8_t*)q->payload + payloadoffset), byteslefttocopy );
        bufferoffset = bufferoffset + byteslefttocopy;
        framelength = framelength + byteslefttocopy;
    }

    /* Note: padding and CRC for transmitted frame 
        are automatically inserted by DMA */

    /* Prepare transmit descriptors to give to DMA*/ 
    ETH_Prepare_Transmit_Descriptors(framelength);

    errval = ERR_OK;

error:

    /* When Transmit Underflow flag is set, clear it and issue a Transmit Poll Demand to resume transmission */
    if ((ETH->DMASR & ETH_DMASR_TUS) != (uint32_t)RESET)
    {
        /* Clear TUS ETHERNET DMA flag */
        ETH->DMASR = ETH_DMASR_TUS;

        /* Resume DMA transmission*/
        ETH->DMATPDR = 0;
    }
    return errval;
}

/**
 * Should allocate a pbuf and transfer the bytes of the incoming
 * packet from the interface into the pbuf.
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return a pbuf filled with the received packet (including MAC header)
 *         NULL on memory error
   */
static struct pbuf * low_level_input(struct netif *netif)
{
    struct pbuf *p, *q;
    uint32_t len;
    FrameTypeDef frame;
    u8 *buffer;
    __IO ETH_DMADESCTypeDef *DMARxDesc;
    uint32_t bufferoffset = 0;
    uint32_t payloadoffset = 0;
    uint32_t byteslefttocopy = 0;
    uint32_t i=0;

    /* get received frame */
    frame = ETH_Get_Received_Frame();

    /* Obtain the size of the packet and put it into the "len" variable. */
    len = frame.length;
    buffer = (u8 *)frame.buffer;

    if (len > 0)
    {
        /* We allocate a pbuf chain of pbufs from the Lwip buffer pool */
        p = pbuf_alloc(PBUF_RAW, len, PBUF_POOL);
    }

    if (p != NULL)
    {
        DMARxDesc = frame.descriptor;
        bufferoffset = 0;
        for(q = p; q != NULL; q = q->next)
        {
            byteslefttocopy = q->len;
            payloadoffset = 0;

            /* Check if the length of bytes to copy in current pbuf is bigger than Rx buffer size*/
            while( (byteslefttocopy + bufferoffset) > ETH_RX_BUF_SIZE )
            {
                /* Copy data to pbuf*/
                memcpy( (u8_t*)((u8_t*)q->payload + payloadoffset), (u8_t*)((u8_t*)buffer + bufferoffset), (ETH_RX_BUF_SIZE - bufferoffset));

                /* Point to next descriptor */
                DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
                buffer = (unsigned char *)(DMARxDesc->Buffer1Addr);

                byteslefttocopy = byteslefttocopy - (ETH_RX_BUF_SIZE - bufferoffset);
                payloadoffset = payloadoffset + (ETH_RX_BUF_SIZE - bufferoffset);
                bufferoffset = 0;
            }
            /* Copy remaining data in pbuf */
            memcpy( (u8_t*)((u8_t*)q->payload + payloadoffset), (u8_t*)((u8_t*)buffer + bufferoffset), byteslefttocopy);
            bufferoffset = bufferoffset + byteslefttocopy;
        }
    }

    /* Release descriptors to DMA */
    DMARxDesc =frame.descriptor;

    /* Set Own bit in Rx descriptors: gives the buffers back to DMA */
    for (i=0; i<DMA_RX_FRAME_infos->Seg_Count; i++)
    {
        DMARxDesc->Status = ETH_DMARxDesc_OWN;
        DMARxDesc = (ETH_DMADESCTypeDef *)(DMARxDesc->Buffer2NextDescAddr);
    }

    /* Clear Segment_Count */
    DMA_RX_FRAME_infos->Seg_Count =0;

    /* When Rx Buffer unavailable flag is set: clear it and resume reception */
    if ((ETH->DMASR & ETH_DMASR_RBUS) != (u32)RESET)
    {
        /* Clear RBUS ETHERNET DMA flag */
        ETH->DMASR = ETH_DMASR_RBUS;
        /* Resume DMA reception */
        ETH->DMARPDR = 0;
    }
    return p;
}

/**
 * This function should be called when a packet is ready to be read
 * from the interface. It uses the function low_level_input() that
 * should handle the actual reception of bytes from the network
 * interface. Then the type of the received packet is determined and
 * the appropriate input function is called.
 *
 * @param netif the lwip network interface structure for this ethernetif
 */
err_t ethernetif_input(struct netif *netif)
{
    err_t err;
    struct pbuf *p;

    /* move received packet into a new pbuf */
    p = low_level_input(netif);

    /* no packet could be read, silently ignore this */
    if (p == NULL) return ERR_MEM;

    /* entry point to the LwIP stack */
    err = netif->input(p, netif);

    if (err != ERR_OK)
    {
        LWIP_DEBUGF(NETIF_DEBUG, ("ethernetif_input: IP input error\n"));
        pbuf_free(p);
    }
    return err;
}

static struct netif *input_netif;
err_t ethernetif_post(struct netif *netif)
{
    input_netif = netif;

#if NO_SYS
#else
    sys_sem_signal_fromisr(eth_input_sem);
#endif
}
#if NO_SYS
#else
static void eth_input_thread(void *arg)
{
    while (1)
    {
        sys_arch_sem_wait(&eth_input_sem, 0);

        while(ETH_CheckFrameReceived()){
            ethernetif_input(input_netif);
        }
    }
}
#endif

static void arp_timer(void *arg)
{
    etharp_tmr();
    sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);
}

/**
 * Should be called at the beginning of the program to set up the
 * network interface. It calls the function low_level_init() to do the
 * actual setup of the hardware.
 *
 * This function should be passed as a parameter to netif_add().
 *
 * @param netif the lwip network interface structure for this ethernetif
 * @return ERR_OK if the loopif is initialized
 *         ERR_MEM if private data couldn't be allocated
 *         any other err_t on error
 */
err_t ethernetif_init(struct netif *netif)
{
    LWIP_ASSERT("netif != NULL", (netif != NULL));

#if LWIP_NETIF_HOSTNAME
    /* Initialize interface hostname */
    netif->hostname = "stm32_net";
#endif /* LWIP_NETIF_HOSTNAME */

    netif->name[0] = IFNAME0;
    netif->name[1] = IFNAME1;
    /* We directly use etharp_output() here to save a function call.
    * You can instead declare your own function an call etharp_output()
    * from it if you have to do some checks before sending (e.g. if link
    * is available...) */
    netif->output = etharp_output;
    netif->linkoutput = low_level_output;

    /* initialize the hardware */
    low_level_init(netif);

    etharp_init();
    sys_timeout(ARP_TMR_INTERVAL, arp_timer, NULL);

    return ERR_OK;
}

